Physiology- Muscular Flashcards
What is the contractile until of muscle?
sarcomere
What is the name of the organelle in the muscle cell that is high in calcium?
sarcoplasmic reticulum
What is the neurotransmitter of the neuromuscular junction?
acetylcholine
What substance fluxes through open gated channels when the action potential reaches the terminal bouton?
calcium
The depolarization of the post-synaptic membrane is known as what?
The end plate potential
Why will the end plate potential always reach threshold every time?
because it is a suprathreshold
What stops the action of acetylcholine in the synaptic cleft?
acetyl choline esterase
Adrenergic synapses use what neurotransmitter?
norepinephrine
What are the 2 contractile proteins of muscle?
Actin and myosin
Which of the contractile proteins is found in the thin filament?
actin
Which of the contractile proteins is found in the thick filament?
myosin
What are the 2 regulatory proteins that are also found on the thin filament?
troponin, tropomyosin
Which is the regulatory protein that has an inhibitory action on the formation of actin-myosin complex?
tropomyosin
What substance causes the troponin-tropomyosin complex to fall away from the active site of the actin molecule?
calcium
to which of the regulatory proteins does calcium bind?
troponin
What substance is bound to the myosin head?
ATP
What two things do we need to get the muscle to relax?
- Removal of calcium
2. ATP bound to the myosin head
Lifting and setting down contraction with muscle shortening and lengthening is known as what type of contraction?
Isotonic
Contraction with no external muscle shortening is what type of contraction?
Isometric
The force-velocity curve depicts what type of muscle contraction?
isotonic (velocity indicates movement)
The length-tension curve depicts what type of muscle contraction?
Isometric
Posture, heat generation, nerve nutrition of muscle and general circulation are all function of what?
muscle tone
What is it called when a series of action potentials reach a muscle such that it cannot relax and so force within a muscle is built to a maximum?
summation of twitches –> tetany
Accumulation of calcium in the cytoplasm is the mechanism for what?
summation of twitches
What are the 3 muscle types?
Fast oxidative glycolytic
Slow oxidative
Fast glycolytic
Marathon runners have more of what muscle fiber?
slow oxidative
Sprinter have more of what type of muscle fiber?
fast glycolytic
Where do you find smooth muscle in the body?
Hollow organs, blood vessels, lymphatics, skin (piloerection), eye
What are the 2 different types of smooth muscle?
- Multi unit
2. visceral-contracts as a single unit
Piloerection and the ciliary muscles of the eyes are examples of what type of muscle?
multi unit smooth muscle
Gap junctions are found in which type of smooth muscle?
viscera (single unit)
What is the cytoplasmic binding protein found in smooth muscle?
Calmodulin
What are 2 possible sources of calcium for smooth muscle contraction?
- mitochonrion
2. intracellular vescicles
How does relaxation of smooth muscle differ from relaxation of skeletal muscle?
It requires a light chain phosphates enzyme to remove phosphate from myosin. In skeletal muscle, relaxation is based on the repute of calcium and ATP binding to myosin head
What are the 2 types of action potentials in smooth muscle?
- spike potential
2. Plateau potential
The gut, blood vessels experience what type of smooth muscle action potential?
spike
The uterus and bladder experience what type of smooth muscle action potential?
plateau potential
Smooth muscle contraction is regulated in what 2 ways?
- Neurally i.e. via neurotransmitters
2. hormonally via blood borne agents (epic), local tissue factors (O2, CO2, H+)
What happens to smooth muscle when it is stretched?
It will often lead to a spike potential and a contraction
